style.css

@keyframes errors {
    from {
      margin-top: -5px;
      opacity: .1; 
    }
  
    to {
      margin-top: 10px;
      opacity: 1;
    }
}

html {
    font-family: Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 600px;
    margin: auto;
}

.header {
    max-width: 600px;
    height: 80px;
    margin: auto;
    display: flex;
    align-items: center;
}

.header__logo {
    width: 150px;
}

.header__logo-sub {
    margin-left: 10px;
    margin-bottom: 25px;
    font-size: 0.6em;
}

.form {
    max-width: 600px;
    margin: auto;
}

.block {
    margin-top: 60px;
    border-radius: 3px;
  }

.cover {
    display: flex;
    align-items: center;
    margin-top: 30px;
    margin-bottom: 20px;
  }

.cover__image {
    width: 110px;
    min-width: 110px;
    height: 110px;
    background-image: url(https://pictures.s3.yandex.net/frontend-developer/dom_bom/cover.jpg);
    background-size: cover;
    background-position: center;
    border-radius: 50%;
}
  
.cover__heading {
    margin-left: 30px;
    font-size: 2.5em;
    line-height: 1;
}

.form__field {
	margin-bottom: 36px;
}

.form__fieldset {
    border: none;
    margin: 0;
    padding: 0;
}

.form__error {
    display: none;
    position: absolute;
    margin-top: 10px;
	color: #df4b41;
	text-align: left;
	font-size: 14px;
    animation: errors .1s ease-in-out;
}

.form__input {
    display: block;
    width: 100%;
    border: none;
	border-radius: 2px;
	border-bottom: 2px solid #ccc;
	padding: 10px 0;
    box-sizing: border-box;
    font-size: 16px;
}

.form__button {
    width: 200px;
    height: 48px;
    font-weight: bold;
    font-size: 14px;
    border-radius: 3px;
    border: none;
    text-align: center;
    cursor: pointer;
	background-color: #ffdb4d;
	color: #000;
}

.form__input:valid:not(:placeholder-shown) {
	border-color: #ffdb4d;
}

.form__input:invalid:not(:placeholder-shown) {
	border-color: #df4b41;
}

.form__input:invalid:not(:placeholder-shown) + .form__error {
	display: block;
}